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MILL DEPTH STOP

WMT300/2 (similar to the Clarke, Grizzly 4015 and Smithy 1220)

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This is a write up of a depth stop experiment I am currently working on.
I wanted to add a depth stop facility to the mill, and also try and make the quill a touch more rigid.
I figured that a beefy depth stop that is attached to the quill nose will help to steady the quill. Every little helps.

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I have already made the quill nose plate that this depth stop will be connected to.
Please refer to the 'quill nose plate' page.

The depth stop will be attached to the mill casting just below the existing quill lock grub screw.
I could have attached the depth stop in the quill lock grub screw thread but I wanted to keep that just in case all this did not work out.

So, the first thing to do is drill a new hole in the mill head casting.
The quill assembly will have to be removed before any drilling is done.
Please refer to the 'quill removal' page.

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↓ I removed the quill and drilled and tapped an M8 hole in the mill head casting. I then reinstalled the quill assembly.
The new hole is the lower one of the two.

 

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I started off making the 'base plate' for the depth stop.
I did not want to make lots of holes in the casting, so the plate is attached to the casting by one M8 bolt.
The area where the plate is attached is curved and not symmetrical and a bit of a problem to fix to.
I opted to use 4 small adjusting screws to adjust the angle of the plate on this curved area.
The adjusting screws will bear down on the outside of the casting. Basically it is like a 4 legged table firmly fixed to the casting.

↓ Here is the intial test piece, to see if it would work.
It looks like the base plate can be rigidly fixed using the M8 bolt and 4 adjuster screws .
Note the gap (due to the curve of the casting) at the left of the base plate.

 

↓ The base plate fouls the existing M8 quill lock hole, so a U channel is milled.
The mill did not do a good job. I had already taken off too much so I had to leave it.

 

 

↓ The four adjuster screw holes are drilled and tapped M4.
The two fixing holes for the 'block' are drilled and tapped M6.

 

↓ That cap head is standing a little proud. I will mill a little off the cap head later.

 

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↓ The 4 off M4 adjuster screws were made from that 'All Thread' stuff.
The slots in the screws were done using the slitting saw.

 

 

 

↓ Here are the screws after slotting. I made an extra one.

 

↓ Here are the screws after finishing in the lathe.
Note the pointed ends.

 

 

↓ The adjuster screws are inserted in the plate.

 

 

 

 

↓ The base plate is lined up to the quill nose plate using a set square and a screwdriver on the adjusters.

 

 

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↓ The 'block' was made next.
It is an odd color because it is cut from a rusty old bar.
The block is marked out and the majority of the cutting is done in the bandsaw.
I should have bored the hole first, but I was rushing again.
I quickly bored the hole in the lathe before making the final cuts.

 

 

 

↓ I bored the hole to 19mm (3/4"), then made the final cuts.
The finals cuts are made by hand.

 

 

↓ The top was trued up with a fly cutter.

 

↓ The depth stop rod was tested in the bore.
It is a nice tight sliding fit.

 

 

 

 

↓ The sides of the block were milled to the lines with an end mill.
The surfaces were then finished by hand filing, because I do not like the fish scale pattern left by an end mill.

 

 

↓ The top of the block was drilled and tapped M8.
Two 6mm fixing hole were drilled and counterbored, to house the M6 cap screws.

 

 

 

 

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↓ The block is fixed to the base plate.
Unexpectedly I found I had to cut some corners off, so that the bottom adjuster screws were not covered.
Needless to say, I rushed again. I now think I should not have done the cut. I might put a radius or bevel on that 'too square looking' cut out soon.
The nice filed surface is already getting scratched.

 

↓ Note the access to the original quill lock.

 

↓ I drilled and tapped the depth stop rod for an M10 stud. I put a point on the stud, and it helped to mark the hole position on the quill nose plate.

 

 

↓ The depth stop rod lines up with the quill nose plate quite nicely.

 

↓ The depth stop rod attached to the quill nose plate.
I will lose the pointy bit at some stage.

 

↓ The 19mm diameter depth stop rod, quill, and quill nose plate all move up and down without any binding or slop. I am pleased about this.

 

↓ This shows the gap behind that base plate. Note the adjuster screw.
If it turns out to not be rigid enough I can always beef that area up somehow.

 

↓ The M8 cap screw can be used to lock the depth stop rod, and hence help lock and steady the quill.
The M8 fixing is also used to mount a dti assembly.

 

 

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↓ Here are the components so far.

 

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↓ Here are the depth stop adjusting components.
I milled an 8mm slot in the depth stop vertical rod.
Unfortunately I had to mill away part of the stud that attached the depth stop rod to the quill nose plate, but this is only a cosmetic thing and does not affect the workings.

 

↓ Here is a close up of the locking collar and thumbscrew.

 

 

↓ Here are the installed components.
The slot in the depth stop rod is getting marked by the thumbscrew and dti mount locking screw.
That is the intention, as the outside of the rod remains unmarked and runs smoothly in the bore in the block.

 

 

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There are a few parts to make to finish this.
Also, all the parts need filing and finishing properly at some time.

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